Orientation Programming For 4-Axis Kinematics - Siemens SINUMERIK 840D sl Function Manual

The coordinate system in which motion is executed is defined using the ORIWKS and
ORIMKS commands.
Syntax
ORIWKS
ORIMKS
Meaning
ORIWKS:
ORIMKS:
Note
● ORIWKS is the preferred approach for a program independent of a particular machine.
● It is not possible to program the tool orientation using Euler angles, RPY angles or direction
vectors for kinematics involving fewer than 5 axes. For 4-axis kinematics with only one
rotary axis, there is only one degree of freedom for orientation. This orientation angle can
only be programmed with orientation axis angle "A".
● Transferring an orientation using ORIMKS is not allowed in the handling transformation
package. With an active transformation, the machine axis angles are not programmed and
traversed, but rather the "orientation angles" (RPY angles according to robotics definition,
see Section "Definition of positions and orientations using frames (Page 637)").
17.6.1

Orientation programming for 4-axis kinematics

Tool orientation for 4-axis kinematic
4-axis kinematics possess only one degree of freedom for orientation. When the orientation is
programmed using RPY angles, Euler angles or direction vectors, it is not generally possible
to guarantee that the specified orientation can be approached. If used at all, this type of
orientation programming is only suitable for certain types of kinematic, i.e. those which feature
an invariance in orientation angles relative to the basic axes. This is the case for the SCARA
kinematic, for example.
For this reason, orientation programming is only permitted via "orientation angle" A for 4-axis
kinematics. This angle corresponds to the RPY angle C according to the robotics definition,
i.e. one rotation about the Z-RO axis, as illustrated in Fig. "Orientation angle for 4-axis
kinematic".
Special functions
Function Manual, 01/2015, 6FC5397-2BP40-5BA2
Tool orientation in the workpiece coordinate system (WCS)
In the case of a change in orientation with the tool tip at a fixed point in space, the tool
moves along a large arc on the plane extending from the start vector to the end vector.
Transitioning a tool orientation at the start of a block to an orientation at the end of the
block is only possible in the WCS.
Effective: Modal
Tool orientation in the machine coordinate system (MCS)
In the case of a change in orientation of a tool tip at a fixed point in space, linear
interpolation takes place between the rotary axis positions.
Effective: Modal
TE4: Handling transformation package - 840D sl only
17.6 Tool orientation
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